// This file is part of Eigen, a lightweight C++ template library
// for linear algebra.
//
// Copyright (C) 2008-2010 Gael Guennebaud <gael.guennebaud@inria.fr>
//
// This Source Code Form is subject to the terms of the Mozilla
// Public License v. 2.0. If a copy of the MPL was not distributed
// with this file, You can obtain one at http://mozilla.org/MPL/2.0/.

#ifndef EIGEN_ASSIGNMENT_FUNCTORS_H
#define EIGEN_ASSIGNMENT_FUNCTORS_H

namespace Eigen {

namespace internal {

/** \internal
 * \brief Template functor for scalar/packet assignment
 *
 */
template<typename DstScalar, typename SrcScalar>
struct assign_op
{

	EIGEN_EMPTY_STRUCT_CTOR(assign_op)
	EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void assignCoeff(DstScalar& a, const SrcScalar& b) const { a = b; }

	template<int Alignment, typename Packet>
	EIGEN_STRONG_INLINE void assignPacket(DstScalar* a, const Packet& b) const
	{
		internal::pstoret<DstScalar, Packet, Alignment>(a, b);
	}
};

// Empty overload for void type (used by PermutationMatrix)
template<typename DstScalar>
struct assign_op<DstScalar, void>
{};

template<typename DstScalar, typename SrcScalar>
struct functor_traits<assign_op<DstScalar, SrcScalar>>
{
	enum
	{
		Cost = NumTraits<DstScalar>::ReadCost,
		PacketAccess = is_same<DstScalar, SrcScalar>::value && packet_traits<DstScalar>::Vectorizable &&
					   packet_traits<SrcScalar>::Vectorizable
	};
};

/** \internal
 * \brief Template functor for scalar/packet assignment with addition
 *
 */
template<typename DstScalar, typename SrcScalar>
struct add_assign_op
{

	EIGEN_EMPTY_STRUCT_CTOR(add_assign_op)
	EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void assignCoeff(DstScalar& a, const SrcScalar& b) const { a += b; }

	template<int Alignment, typename Packet>
	EIGEN_STRONG_INLINE void assignPacket(DstScalar* a, const Packet& b) const
	{
		internal::pstoret<DstScalar, Packet, Alignment>(a, internal::padd(internal::ploadt<Packet, Alignment>(a), b));
	}
};
template<typename DstScalar, typename SrcScalar>
struct functor_traits<add_assign_op<DstScalar, SrcScalar>>
{
	enum
	{
		Cost = NumTraits<DstScalar>::ReadCost + NumTraits<DstScalar>::AddCost,
		PacketAccess = is_same<DstScalar, SrcScalar>::value && packet_traits<DstScalar>::HasAdd
	};
};

/** \internal
 * \brief Template functor for scalar/packet assignment with subtraction
 *
 */
template<typename DstScalar, typename SrcScalar>
struct sub_assign_op
{

	EIGEN_EMPTY_STRUCT_CTOR(sub_assign_op)
	EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void assignCoeff(DstScalar& a, const SrcScalar& b) const { a -= b; }

	template<int Alignment, typename Packet>
	EIGEN_STRONG_INLINE void assignPacket(DstScalar* a, const Packet& b) const
	{
		internal::pstoret<DstScalar, Packet, Alignment>(a, internal::psub(internal::ploadt<Packet, Alignment>(a), b));
	}
};
template<typename DstScalar, typename SrcScalar>
struct functor_traits<sub_assign_op<DstScalar, SrcScalar>>
{
	enum
	{
		Cost = NumTraits<DstScalar>::ReadCost + NumTraits<DstScalar>::AddCost,
		PacketAccess = is_same<DstScalar, SrcScalar>::value && packet_traits<DstScalar>::HasSub
	};
};

/** \internal
 * \brief Template functor for scalar/packet assignment with multiplication
 *
 */
template<typename DstScalar, typename SrcScalar = DstScalar>
struct mul_assign_op
{

	EIGEN_EMPTY_STRUCT_CTOR(mul_assign_op)
	EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void assignCoeff(DstScalar& a, const SrcScalar& b) const { a *= b; }

	template<int Alignment, typename Packet>
	EIGEN_STRONG_INLINE void assignPacket(DstScalar* a, const Packet& b) const
	{
		internal::pstoret<DstScalar, Packet, Alignment>(a, internal::pmul(internal::ploadt<Packet, Alignment>(a), b));
	}
};
template<typename DstScalar, typename SrcScalar>
struct functor_traits<mul_assign_op<DstScalar, SrcScalar>>
{
	enum
	{
		Cost = NumTraits<DstScalar>::ReadCost + NumTraits<DstScalar>::MulCost,
		PacketAccess = is_same<DstScalar, SrcScalar>::value && packet_traits<DstScalar>::HasMul
	};
};

/** \internal
 * \brief Template functor for scalar/packet assignment with diviving
 *
 */
template<typename DstScalar, typename SrcScalar = DstScalar>
struct div_assign_op
{

	EIGEN_EMPTY_STRUCT_CTOR(div_assign_op)
	EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void assignCoeff(DstScalar& a, const SrcScalar& b) const { a /= b; }

	template<int Alignment, typename Packet>
	EIGEN_STRONG_INLINE void assignPacket(DstScalar* a, const Packet& b) const
	{
		internal::pstoret<DstScalar, Packet, Alignment>(a, internal::pdiv(internal::ploadt<Packet, Alignment>(a), b));
	}
};
template<typename DstScalar, typename SrcScalar>
struct functor_traits<div_assign_op<DstScalar, SrcScalar>>
{
	enum
	{
		Cost = NumTraits<DstScalar>::ReadCost + NumTraits<DstScalar>::MulCost,
		PacketAccess = is_same<DstScalar, SrcScalar>::value && packet_traits<DstScalar>::HasDiv
	};
};

/** \internal
 * \brief Template functor for scalar/packet assignment with swapping
 *
 * It works as follow. For a non-vectorized evaluation loop, we have:
 *   for(i) func(A.coeffRef(i), B.coeff(i));
 * where B is a SwapWrapper expression. The trick is to make SwapWrapper::coeff behaves like a non-const coeffRef.
 * Actually, SwapWrapper might not even be needed since even if B is a plain expression, since it has to be writable
 * B.coeff already returns a const reference to the underlying scalar value.
 *
 * The case of a vectorized loop is more tricky:
 *   for(i,j) func.assignPacket<A_Align>(&A.coeffRef(i,j), B.packet<B_Align>(i,j));
 * Here, B must be a SwapWrapper whose packet function actually returns a proxy object holding a Scalar*,
 * the actual alignment and Packet type.
 *
 */
template<typename Scalar>
struct swap_assign_op
{

	EIGEN_EMPTY_STRUCT_CTOR(swap_assign_op)
	EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void assignCoeff(Scalar& a, const Scalar& b) const
	{
#ifdef EIGEN_GPUCC
		// FIXME is there some kind of cuda::swap?
		Scalar t = b;
		const_cast<Scalar&>(b) = a;
		a = t;
#else
		using std::swap;
		swap(a, const_cast<Scalar&>(b));
#endif
	}
};
template<typename Scalar>
struct functor_traits<swap_assign_op<Scalar>>
{
	enum
	{
		Cost = 3 * NumTraits<Scalar>::ReadCost,
		PacketAccess =
#if defined(EIGEN_VECTORIZE_AVX) && EIGEN_COMP_CLANG && (EIGEN_COMP_CLANG < 800 || defined(__apple_build_version__))
			// This is a partial workaround for a bug in clang generating bad code
			// when mixing 256/512 bits loads and 128 bits moves.
			// See http://eigen.tuxfamily.org/bz/show_bug.cgi?id=1684
			//     https://bugs.llvm.org/show_bug.cgi?id=40815
		0
#else
			packet_traits<Scalar>::Vectorizable
#endif
	};
};

} // namespace internal

} // namespace Eigen

#endif // EIGEN_ASSIGNMENT_FUNCTORS_H
